The present invention relates generally to the art of electrical connectors and, more particularly, to a "card edge" electrical connector for a printed circuit board. In even greater particularity, the present invention relates to dual-beam ground contacts having a realignment twist for gang insertion into the insulator housing of a card edge electrical connector.
Historically, prior art electrical connectors have been assembled by very tightly press fitting or molding contacts into receiving blocks of insulative material which form structural members to support the contacts and hold them rigidly within the insulative body. The prior art connector having contacts rigidly fixed within the insulator are then mounted by bolting the insulator to a pair of spaced parallel rails, or by dropping the contact tails into holes in a mounting substrate and soldering them in place. The prior art techniques for assembly of the aforesaid connectors are relatively slow because of the time required to rigidly mount each individual contact into its receiving sleeve within the insulator. Certain prior art connectors have overcome this problem by providing for simultaneous insertion of rows of contacts held together by carrier strips into receiving sleeves which hold them in position within the insulator housing.
A popular type of electrical connector which is used widely in the electronic industry is called a "card edge" connector. A card edge connector receives a printed circuit board having a mating edge and a plurality of contact pads adjacent the edge. Such card edge connectors typically have an elongate insulator housing defining an elongate receptacle or slot for receiving the mating edge of the printed circuit board. A plurality of contacts are spaced along one or both sides of the slot for engaging the contact pads adjacent the mating edge of the board. In many applications, such card edge connectors are mounted on a second printed circuit board. The mating edge board or card is commonly called a "daughter" board, and the board to which the connector is mounted commonly is called the "mother" board.
One of the problems with card edge connectors of the character described above, however, centers around the ever-increasing demands for high density electronic circuitry. The contacts of such a connector are mounted in a housing fabricated of dielectric material such as plastic or the like. Not only are the contacts becoming ever-increasingly miniaturized, but their number or density within the housing is becoming greater and greater, thus significantly increasing the likelihood of short circuiting between the respective contacts. In order to solve the potential problem of short circuiting, separate sleeves may be designed into the housing to partition the contacts so that they are electrically isolated from one another. This technique is very difficult and cost prohibitive because of the miniaturized size and number of contacts. A more viable solution has been to fashion or form the contacts into specific shapes to avoid shorting or being shorted by other contacts. An example of this technique is to pre-load or bend the tip of certain contacts to avoid other non-preloaded contacts within the insulator housing.
However, even pre-loading the tips of contacts to avoid short-circuiting suffers from the standpoint of assembly. While a typical card edge connector utilizes a plurality of contacts formed out of sheet material on a common carrier strip so that they can be simultaneously inserted into the insulator housing, the above described technique of pre-loading tends to offset or mis-align the tips of the contacts with the spacing or pitch of the correct insulator housing slots or cavities, thus preventing simultaneous gang insertion of the contacts. As a result, the tips of pre-loaded contacts typically have to be inserted into the insulator one-by-one.
It is, therefore, desirous to provide electrical contacts which may be manufactured in quantity from sheet material on a carrier strip having pre-loaded tips, yet may be gang inserted into an insulator housing.